Optical particle sizer (OPS), optical particle counter (OPC), and aethalomter were deployed to measure the particle number concentrations from 0.3 to and black carbon (BC) concentrations. Comparisons of particle number concentrations measured by OPS and OPC were conducted to evaluate the performance of the each optical instrument at the Gwangju sampling site (, ) for 14 days from Dec. 27 in 2014. Although a good correlation ($r^2

Ozone has been a problem in big cities. That is secondary air pollutant produced by nitrogen oxide and VOCs in the atmosphere. In order to solve this, the first to be the analysis of the and VOCs. The main source of nitrogen oxide is the road mobile. Industrial sources in Seoul are particularly low, and mobile traffics on roads are large, so 45% of total are estimated that road mobile emissions in Seoul. Thus, it is necessary to clarify the relation with the activity of road mobile source and concentration. In this study, we analyzed the 4 locations with roadside automatic monitoring systems in their center. The V.K.T. calculating areas are set in circles with 50 meter spacing, 50 meter to 500 meter from their center. We assumed the total V.K.T. in the set radius affect the concentration in the center. We used the hourly concentrations data for the 4 observation points in July for the interference of the other sources are minimized. We used the intersection traffic survey data of all direction for construction of the V.K.T. data, the mobile activities on the roads. ArcGIS application was used for calculating the length of roads in the set radius. The V.K.T. data are multiplied by segment traffic volume and length of roads. As a result, the concentration can be expressed as linear function formula for V.K.T. with high predictive power. Moreover we separated background concentration and concentrations due to road mobile source. These results can be used for forecasting the effect of traffic demand management plan.

Organic carbon (OC) and elemental carbon (EC) in were measured with Sunset OC/EC Field Analyzer at Taehwa Research Forest (TRF) near Seoul metropolitan area from May 2013 to April 2014. During the study period, the mean concentrations of OC and EC were and , respectively. They showed clear seasonality reaching their maximum in winter ( and ) and minimum in wet summer ( and ). While OC showed greater seasonal variation, the diurnal variation was more noticeable for EC through all seasons with a clear maximum in the morning, which reveals the influence of vehicle emissions. In contrast, OC exhibited a broad second peak in the afternoon during May~June, when biological activities were the highest. Using the morning peaks of EC and OC, primary OC/EC ratio was assessed, which was assumed to be anthropogenic origin. It was the greatest in winter followed by spring and the lowest in wet summer. The seasonal difference in primary OC/EC ratio implies the influence of non-local sources of OC at the Mt. Taehwa.

The anthropogenic aerosols originated from the pollutant emissions in the eastern part of China and dust emitted in northwestern China in Yellow sand regions are subsequently transported via eastward wind to the Korean peninsula and then these aerosols induce high concentrations in Korean peninsula. In order to estimate air quality considering anthropogenic and dust emissions, Comprehensive Air-quality Model with extension (CAMx) was applied to simulate concentration. The predicted concentrations without/with dust emissions were compared with observations at ambient air quality monitoring sites in China and Korea for 2008. The predicted concentrations with dust emissions could depict the variation of measured especially during Yellow sand events in Korea. The comparisons also showed that predicted concentrations without dust emissions were under-predicted while predictions of concentrations with dust emission were in good agreement with observations. This implied that dust emissions from desert and barren soil in southern Mongolia and northern China minimized the discrepancies in the predictions in East Asia. The effect of dust emission on annual concentrations in Korea Peninsula for year 2008 was , which were about 20% of observed annual concentrations.

In order to analyze the surface temperature in accordance with the surface material, surface temperatures between Thermal InfraRed Image (TIRI) and Landsat 8 satellite observed at the commercial area (Gwanghwamun) and residential area (Jungnang) are compared. The surface temperature from TIRI had applied atmospheric correction and compared with that from Landsat 8. The surface temperatures from Landsat 8 at Gwanghwamun and Jungnang are underestimated in comparison with that from TIRI. The difference of surface temperature between the two methods is greater in summer than in winter. When the analysis area was divided into detailed regions, depending on the material and the position of the surface, correlation of surface temperature between TIRI with Landsat 8 is as low as 0.29 (Gwanghwamun) and 0.18 (Jungnang), respectively. The results were caused from the resolution difference between the two methods. While the surface temperatures of each zone from Landsat 8 were observed almost constant, high-resolution TIRI observed relatively precise surface temperatures. When the each area was averaged as one space, correlation of surface temperature between TIRIs and Landsat 8 is more than 0.95. The spatially averaged surface temperature is higher at Jungnang, representing residential areas, than at Gwanghwamun, representing commercial areas. As a result, the observation of high resolution is required in order to observe the precise surface temperature. This is because it appears that the spatial distribution of the various surface temperature in the range of micro-scale according to the conditions of the ground surface.

Aerosol optical thickness (AOT) and exponents were monitored at the KIU site (, ) during the continuous observation period of 5 November 2010~19 March 2013 using a Microtops-II handheld munti-wavelenth radiometer. Comparisons of AOT values from the Microtops-II with the Sun-sky radiometer data from the Aerosol Robotic Network (AERONET) showed very good agreements: correlation coefficients are lies between 0.98 and 0.99, slopes range from 0.98 to 1.01, and intercepts are smaller than 0.008 at five wavelengths (380 nm, 440 nm, 500 nm, 675 nm, 870 nm). During the observation period, the Microtops-II AOT and exponents are ${\tau}_{500}

In order to examine the variation characteristics of chemical compositions in accordance with the different meteorological conditions, and were collected at Gosan site of Jeju Island in 2014, and then their ionic and elemental species were analyzed. The concentrations of nss- and were respectively 4.3 and 3.3 times higher in fine particle mode () compared to coarse particle mode (), however concentration was 1.6 times higher in coarse mode compared to fine particle mode. During Asian dust days, the concentrations of nss- and increased highly as 7.7 and 4.5 times in coarse particle mode, and 3.0 and 4.9 times higher in fine particles, respectively. Especially, the concentrations of the crustal species (Al, Fe, Ca, K, Mn, Ba, Sr, etc.) indicated a noticeable increase during the Asian dust days. For the haze days, the concentrations of secondary pollutants increased 2.2~2.7 and 2.9~6.0 times in coarse and fine particles, respectively, and they were 0.8~1.1 and 1.8~2.4 times, respectively, during the mist days. The aerosols were acidified largely by sulfuric and nitric acids, and neutralized mainly by ammonia in fine particle mode during the haze days, but neutralized by calcium carbonate in coarse particle mode during the Asian dust days. The clustered back trajectory analysis showed that the concentrations of nss-, , and were relatively high when the inflow pathway of air mass was from the southern part of China.

This study was carried out to understand the regional contribution of Particulate Matter (PM) emissions from East Asia (, ) to Seoul during high concentration period in February 2014. The Community Multi-scale Air Quality (CMAQ) version 5.0.2 with Decoupled Direct Method (DDM) was used to analyze levels of contributions over Seoul. In order to validate model performance of the CMAQ, predicted PM and its chemical species concentrations were compared to observations in China and Seoul. Model predictions could depict the daily and hourly variations of observed PM. The calculated PM concentrations, however, had a tendency of underestimation. The discrepancies are due to uncertainties of meteorological data, emission inventories and CMAQ model itself. The high PM concentration in Seoul was induced by stationary anticyclone over the West Coast of Korea during 24 to 27 February. The DDM in CMAQ was used to analyze the contributions of emissions from East Asia on Seoul during this PM episode. concentration in Seoul is contributed by 39.77%~53.19% from China industrial and urban region, 15.37%~37.10% from South Korea, and 9.03%~18.05% North Korea. These indicate that concentrations in Seoul during the episode period are dominated by long-range transport from China region as well as domestic sources. It was also found that the largest contribution region in China were Shandong peninsula during the PM event period.

In this study, the characteristics of and concentrations were identified in two different functional areas including Chuncheon and Youngwol, Korea. Even though the anthropogenic emission rates of and are approximately four times higher in Youngwol than in Chuncheon their atmospheric concentrations were statistically higher in Chuncheon. In Chuncheon, both concentrations and the ratio of increased as relative humidity (RH) increased possibly because the inorganic and/or organic secondary aerosols were actively formed at high RH. This result was also supported by that concentration was enhanced under the fog and mist conditions in Chuncheon. On the other hand, both and concentrations clearly increased with the southerly winds blown from the cement production facility in Youngwol. In addition, high concentrations were observed with high wind speed, low relative humidity, and high concentrations in Youngwol, suggesting that was generated through the physical process including crushing and packing procedures followed by resuspension from cement and lime factory.

Many cohort studies have reported associations of individual-level long-term exposures to and health outcomes. Individual exposures were often estimated by using exposure prediction models relying on data measured at national regulatory monitoring sites. This study explored spatial and temporal characteristics of regulatory measurement data in South Korea and suggested concentration metrics as long-term exposures for assessing health effects in cohort studies. We obtained hourly data from the National Institute of Environmental Research for 2001~2012 in South Korea. We investigated spatial distribution of monitoring sites using the density and proximity in each of the 16 metropolitan cities and provinces. The temporal characteristics of measurement data were examined by annual/seasonal/diurnal patterns across urban background monitoring sites after excluding Asian dust days. For spatial characteristics of measurement data, we computed coefficient of variation (CV) and coefficient of divergence (COD). Based on temporal and spatial investigation, we suggested preferred long-term metrics for cohort studies. In 2010, 294 urban background monitoring sites were located in South Korea with a site over an area of and distant from another site by 31.0 km on average. Annual average concentrations decreased by 19.8% from 2001 to 2012, and seasonal patterns were consistent over study years with higher concentrations in spring and winter. Spatial variability was relatively small with 6~19% of CV and 21~46% of COD across 16 metropolitan cities and provinces in 2010. To maximize spatial coverage and reflect temporal and spatial distributions, our suggestion for metrics representing long-term exposures was the average for one or multiple years after 2009. This study provides the knowledge of all available data measured at national regulatory monitoring sites in South Korea and the insight of the plausible longterm exposure metric for cohort studies.